1. Field of the Invention
The present invention relates to a propeller shaft for a motor vehicle.
2. Description of the Related Art
As a propeller shaft for a motor vehicle, there has been a structure described in Japanese Patent Application Laid-open No. 2006-151056 (patent document 1). As shown in FIG. 5, the propeller shaft for the motor vehicle fits a shaft-like inner 3 of the constant velocity joint 1C provided in the other split shaft 1B to a tubular outer 2 of the constant velocity joint 1C provided in one split shaft 1A. A bearing 4 is loaded onto a shaft of the inner 3 to an inner periphery of an annular support member 5. The bearing 4 is positioned by stopper means 6 and 7 (the stopper means 7 is integrally formed in the inner 3) provided in the front side and the back side in an axial direction sandwiching the bearing 4 on the shaft of the inner 3, when coupling a plurality of split shafts 1A and 1B by a constant velocity joint 1C. Seal members 8 and 9 provided beside the front side and the back side of an inner periphery supporting the bearing 4 in an inner periphery of the annular support member 5 come into slidable contact with a small diameter portion in an outer periphery of the stopper means 6 and 7. Further, outer ends 5A and 5B extending to outer sides of the front side and the back side in an axial direction of the annular support member 5 come into close contact with a large diameter portion in the outer periphery of the stopper means 6 and 7 in the front side and the back side, and a gap with respect to the large diameter portion of the outer periphery is set to labyrinth seals La and Lb, whereby a muddy water or the like is prevented from making an intrusion into a side of the beating 4 from the gap.
In patent document 1, the gap formed between the outer ends 5A and 5B of the annular support member 5 and the large diameter portion in the outer periphery of the stopper means 6 and 7 is open to an outer side in a radical direction, and the gap open to the outer side is set to an inlet of the labyrinth seals La and Lb. Accordingly, the muddy water scattered from an outer side tends to directly enter into the labyrinth seals La and Lb while keeping a high pressure. The high-pressure muddy water is exposed to a centrifugal force generated by a rotation of the inner 3 so as to travel to a further inner side along the inner periphery of the annular support member 5, and reaches the seal members 8 and 9. The muddy water reaching the seal members 8 and 9 is reserved without being discharged, and there is a risk that an abnormal noise is generated.